[TheForge] Shop Lighting

[Grover Richardson]

Bingo.  Yes, aware of the hazards.  Thanks though!!  Yes, I was trying to
differentiate between what I consider as a normal occurrence of a noble gas
breaking down and nitrogen.  One is done more simply, and the other occurs
only under what I consider extraordinary circumstances<G>.

Thanks.

>*>-----Original Message-----
>*>From: theforge-bounces at mailman.qth.net 
>*>[mailto:theforge-bounces at mailman.qth.net] On Behalf Of Bruce Freeman
>*>Sent: Wednesday, March 01, 2006 4:44 PM
>*>To: theforge at mailman.qth.net
>*>Subject: RE: [TheForge] Shop Lighting
>*>
>*>
>*>Corona results from a high electric field.  Similar, if not 
>*>identical, to what's going on in the fluorescent tube.  
>*>However, I think of corona as an effect around a sharp point 
>*>or very thin wire, at atmospheric pressure.  A fluorescent 
>*>tube is at reduced pressure, so an arc is easier to draw 
>*>(vacuum having less resistance than unionized air) - I 
>*>think.  The glow around a corona is typically the nitrogen 
>*>glow, but may have an oxygen component.  In either case, 
>*>there's UV present, so take care.  And ozone is produced, 
>*>which is not good to breathe.
>*>
>*>What's going on in a neon tube is essentially the same 
>*>thing.  The difference matters to a chemist or physicist, 
>*>but not to a layman.  Namely, nitrogen absorbing energy from 
>*>an arc promotes an electron in a molecular orbital to a 
>*>higher-energy molecular orbital (I'm pretty sure).  Whereas, 
>*>neon absorbing energy from an arc promotes an electron in an 
>*>atomic orbital to a higher-energy atomic orbital.  Real 
>*>important difference, huh? 
>*>
>*>The reason that nitrogen emits UV and neon emits red is that 
>*>the difference in energy between the two molecular orbitals 
>*>of nitrogen happens to correspond to UV (high energy), 
>*>whereas the difference in energy between the two atomic 
>*>orbitals of neon happens to correspond to red light (low energy).
>*>
>*>Bruce
>*>
>*>>>> grover.richardson at gtri.gatech.edu 3/1/2006 11:51:26 AM >>>
>*>Hmm.  Clearing up my understanding.
>*>
>*>Neon breaks down with a gas discharge.  Whereas nitrogen 
>*>glows in the UV due to high Voltage breakdown and/or 
>*>corona??  We get corona all the time around here so am used 
>*>to seeing it.
>*>
>*>>*>-----Original Message-----
>*>>*>From: theforge-bounces at mailman.qth.net
>*>>*>[mailto:theforge-bounces at mailman.qth.net] On Behalf Of 
>*>Bruce Freeman
>*>>*>Sent: Wednesday, March 01, 2006 11:29 AM
>*>>*>To: theforge at mailman.qth.net 
>*>>*>Subject: RE: [TheForge] Shop Lighting
>*>>*>
>*>>*>
>*>>*>Well, that 's not completely true.  Yes, neon is a noble gas 
>*>>*>(a monoatomic gas with almost no tendency to react with 
>*>>*>anything else).  But nitrogen glows in the UV and is not a 
>*>>*>noble gas.  It IS a very stable molecule, though, so maybe 
>*>>*>that helps. 
>*>>*>
>*>>*> But such gases might be chosen simply because they'd be 
>*>>*>less corrosive to the electrodes.  If you used oxygen in the 
>*>>*>tube, it would probably chew through the electrode in no time.
>*>>*>
>*>>*>Bruce
>*>>*>NJ
>*>>*>
>*>>*>>>> grover.richardson at gtri.gatech.edu 3/1/2006 10:58:17 AM >>>
>*>>*>Yes.  If you look at a red "neon sign," you can actually see 
>*>>*>inside the bulb and see the glowing gas.  As I remember it, 
>*>>*>neon glows red and other gasses glow different colors.  Only 
>*>>*>certain gasses will glow, I think they are called the "noble 
>*>>*>gasses."  It's been a loooong time<G>.
>*>>*>
>*>>*>Fun stuff.
>*>>*>
>*>>*>And back to hammering on something else<G>.
>*>>*>
>*>>*>
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